closetime = 0; // Close window after __ number of seconds?
// 0 = do not close, anything else = number of seconds

function Start(URL, WIDTH, HEIGHT) {
windowprops = "left=50,top=50,width=" + WIDTH + ",height=" + HEIGHT;
preview = window.open(URL, "preview", windowprops);
if (closetime) setTimeout("preview.close();", closetime*1000);
}

function doPopup() {
url = "pop.htm";
width = 200;  // width of window in pixels
height = 207; // height of window in pixels
delay = 2;    // time in seconds before popup opens
timer = setTimeout("Start(url, width, height)", delay*1000);
}